Deep-sea vent, hydrothermal (hot-water) vent formed on the ocean floor when seawater circulates through hot volcanic rocks, often located where new oceanic crust is being formed. Vents also occur on submarine volcanoes.
In either case, the hot solution emerging into cold seawater precipitates mineral deposits that are rich in iron, copper, zinc, and other metals. Outflow of those heated waters probably accounts for 20 percent of Earth’s heat loss.
Hydrothermal vents, or hot springs, are areas where geothermally heated water discharges through a planet’s crust onto the surface, either subaerially or subaqueously.
They occur in areas where there is an adequate heat source to drive fluid circulation. On Earth, this heat is primarily derived from tectonic activity near plate boundaries, either through magma generation or faulting.
When were they discovered?
Scientists first discovered hydrothermal vents in 1977 while exploring an oceanic spreading ridge near the Galapagos Islands. To their amazement, the scientists also found that the hydrothermal vents were surrounded by large numbers of organisms that had never been seen before.
How are they formed?
Hydrothermal vents occur where there is volcanic activity and geothermal heating of the seafloor. They are characterized by buoyant plumes of heated water, the temperature of which can vary from slightly above ambient in diffuse flows to over 300°C at intense flows. The precipitation of dissolved minerals when heated water meets cool water can form columnar, chimney-like structures reaching tens of meters into the water column.
World’s deepest sea vents
UK scientists exploring the ocean floor in the Caribbean have discovered an “astounding” set of hydrothermal vents, the deepest anywhere in the world.
Deploying a remotely-operated vehicle (ROV) in the Cayman Trough, they stumbled across a previously-unknown site nearly 5000m below the surface.
The vents blast out some of the hottest water on the planet – it is 400 degrees centigrade. And they have found some unusual wildlife living alongside.
Role in marine life
The hydrothermal vents and methane seeps on the ocean floor that were once thought to be geologic and biological oddities are now emerging as a major force in ocean ecosystems, marine life and global climate. However, even as researchers learn more about their role in sustaining a healthy Earth, these habitats are being threatened by a wide range of human activities, including deep-sea mining.
More than 300 species have so far been identified in deep-sea hydrothermal vent ecosystems, of which over 95% are new to science. Many are restricted to a particular vent field, making each ecosystem unique.
One of the major concerns for scientists is that continuing extracting activity from around the vents could endanger the little-understood marine life that has emerged around these formations.
The reopening or collapse of these vents could also pose a risk to marine life, much of which will be unknown to science. Scientists believe that the heat from deep sea vents is causing immense heat on ocean surface and are helping in glacier melting.
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